JP2006264394A - Travel driving device of dump truck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply a fresh lubrication oil to a reduction mechanism or bearings or the like by efficiently circulating the lubrication oil in an oil reservoir, and improve durability and operating life. <P>SOLUTION: An axle housing 12 provided at a rear wheel 7 side of a vehicle is composed of a motor housing cylinder 14 and a cylindrical spindle 15 detachably provided at the outside in the axial direction of the motor housing cylinder 14. A retainer 61 of a seal device 60 which seals the lubrication oil 100 in an annular space C between the retainer and a wheel mounting cylinder 19 is provided at the outer peripheral side of the cylindrical spindle 15. The retainer 61 is provided with a discharge pipe 69 connected to the position of the lower side than the cylindrical spindle 15. The lubrication oil 100 in the oil reservoir 43 is sucked from the annular space C between the wheel mounting cylinder 19 and the cylindrical spindle 15 through the discharge pipe 69 to discharge in the arrowhead direction D. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a traveling drive device for a dump truck that is preferably used as a large transport vehicle for transporting crushed stones mined at, for example, an open-pit mine, a quarry, a mine, etc. The present invention relates to a traveling drive device for a dump truck configured to increase the rotational torque of the dump truck.

  In general, a large transport vehicle called a dump truck is provided with a vessel (loading platform) that can be raised and lowered on a frame of a vehicle body, and carries a heavy load such as crushed stones on the vessel. .

  For this reason, a travel drive device that travels and drives a drive wheel of a dump truck includes a cylindrical axle housing that is attached to a vehicle body, a drive source such as a hydraulic motor that is provided in the axle housing and rotationally drives a rotating shaft, and the axle A wheel mounting cylinder provided rotatably on a front end side outer periphery of the housing through which a wheel is mounted, and provided between the wheel mounting cylinder and the rotation shaft, the rotation shaft being rotated with respect to the wheel mounting cylinder. A plurality of planetary gear speed reduction mechanisms that transmit by decelerating (see, for example, Patent Documents 1 and 2).

  The multi-stage planetary gear speed reduction mechanism decelerates the rotational output of a drive source such as a hydraulic motor and transmits it to a wheel mounting cylinder (wheel), thereby greatly rotating the drive wheels such as the front wheels or rear wheels of the vehicle. Torque is generated to improve the transport performance of the dump truck (vehicle).

JP-A-5-193373 Japanese Patent Laid-Open No. 9-3000984

  By the way, in the above-described conventional traveling drive device, since a large torque rotational load acts, lubricating oil is supplied to a bearing provided between the axle housing and the wheel mounting cylinder, a multi-stage planetary gear reduction mechanism, and the like. It is necessary to keep these in a lubricated state. In addition, an oil sump is formed in the wheel mounting cylinder for accumulating the lubricating oil at a lower position in the upward and downward directions.

  The lubricating oil stored in the oil reservoir is sucked using a lubricating oil pump or the like provided on the lubricating oil supply source side and sequentially discharged to the outside of the oil reservoir. In addition, on the supply source side, the discharged oil is filtered through an external filter to remove foreign matters (for example, metal powder, wear powder, etc.), and the lubricating oil after being cooled using a cooler or the like is Generally, it is supplied again toward the planetary gear reduction mechanism or the like.

  However, since the traveling drive device of the prior art is configured to discharge the lubricating oil stored in the oil reservoir while sucking it from the inner peripheral side of the axle housing using a discharge pipe or the like, the following The fact is that the problem is occurring.

  In other words, the suction port of the discharge pipe cannot be provided on the rotating wheel mounting cylinder, but needs to be provided on the axle housing side that is not rotated. However, when the lubricating oil in the oil reservoir is sucked into the discharge pipe from the inner peripheral side of the axle housing, it is difficult to suck in foreign matter such as abrasion powder that has accumulated on the lower (bottom) side of the oil reservoir. In this case, used lubricating oil with high oil temperature tends to remain.

  For this reason, in the prior art, new lubricating oil having a low oil temperature cannot be supplied to the bearing provided between the axle housing and the wheel mounting cylinder, and there is a problem that the life of the bearing is reduced. In addition, the planetary gear speed reduction mechanism provided in the wheel mounting cylinder also has a problem that the cooling efficiency is deteriorated due to the lubricating oil having a high oil temperature, and the durability and life are reduced.

  Moreover, in the case of the prior art, the planetary gear speed reduction mechanism is arranged at a position protruding from the axle housing outward in the axial direction. For this reason, there exists a problem that the axial direction length (full length) of the whole traveling drive apparatus becomes long, the whole becomes large and weight increases.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to efficiently circulate lubricating oil in an oil sump and supply fresh lubricating oil to a speed reduction mechanism, a bearing, or the like. Another object of the present invention is to provide a travel drive device for a dump truck that can improve durability and life.

  Another object of the present invention is to provide a dump truck that can be reduced in size and weight as a whole and can also be improved in lubrication performance by housing a part of the speed reduction mechanism in the axle housing. The object is to provide a truck driving device.

  In order to solve the above-described problems, the present invention provides a cylindrical axle housing that is attached to the body of a dump truck in a non-rotating state, a drive source that is provided in the axle housing and rotationally drives a rotating shaft, and the axle housing A wheel mounting cylinder rotatably provided via a bearing on the outer peripheral side of the wheel, and provided between the wheel mounting cylinder and the axle housing, the rotation of the rotating shaft is decelerated relative to the wheel mounting cylinder. The present invention is applied to a travel drive device for a dump truck comprising a speed reduction mechanism that transmits the information.

  A feature of the configuration adopted by the invention of claim 1 is that a lubricating oil supply section that supplies lubricating oil toward the speed reduction mechanism is provided inside the axle housing, and the inside of the axle housing and the wheel mounting cylinder is provided. The lubricating oil supplied from the lubricating oil supply part is accumulated at the lower position in the upper and lower direction, and an oil sump for keeping the bearing in a lubricated state is provided, and the upper and lower direction is lowered on the outer peripheral side of the axle housing. In the side portion, there is provided a configuration in which a lubricating oil discharge portion is provided for sucking and discharging the lubricating oil in the oil reservoir to the outside from between the wheel mounting cylinder and the axle housing.

  According to a second aspect of the present invention, the speed reduction mechanism includes a plurality of planetary gear reduction mechanisms including a sun gear, a ring gear, a planetary gear, and a carrier, and the last stage of the plurality of planetary gear reduction mechanisms. The planetary gear speed reduction mechanism is configured to form the ring gear with an inner diameter dimension close to the outer diameter dimension of the bearing.

  According to a third aspect of the present invention, a guide surface for guiding the lubricating oil in the oil reservoir toward the lubricating oil discharge portion is provided on the inner peripheral surface of the wheel mounting cylinder.

  On the other hand, according to a fourth aspect of the present invention, the axle housing is provided with a cylindrical drive source accommodating portion that accommodates the drive source therein, and is connected to the drive source accommodating portion, and is provided on the inner peripheral side with the speed reduction mechanism. And a cylindrical spindle that rotatably supports the wheel mounting cylinder via the bearing on the outer peripheral side, and the cylindrical spindle seals a liquid-tight seal with the wheel mounting cylinder An annular seal attachment body to which members are attached is provided, and the lubricating oil discharge portion is constituted by a discharge pipe provided connected to the seal attachment body at a position below the cylindrical spindle.

  According to the invention of claim 5, the speed reduction mechanism is constituted by a planetary gear speed reduction mechanism in which a carrier for rotatably supporting a plurality of planetary gears via a support pin is provided in the axle housing in a non-rotating state. The lubricating oil supply section is formed on the supporting pin, the lubricating oil conduit having one side connected to a lubricating oil supply source and the other side extending through the axle housing and connected to the supporting pin of the planetary gear. And a lubricating oil passage through which lubricating oil from the conduit flows toward the planetary gear.

  As described above, according to the first aspect of the present invention, the lubricating mechanism can be lubricated by supplying lubricating oil toward the decelerating mechanism in the axle housing, and the lubricating oil is supplied to the axle housing and the wheel mounting cylinder. The oil can be stored in the oil reservoir provided inside, and the bearing provided between the axle housing and the wheel mounting cylinder can be kept in a lubricated state. A lubricating oil discharge portion that sucks and discharges the lubricating oil in the oil reservoir to the outside from between the wheel mounting cylinder and the axle housing is provided at a lower portion on the outer peripheral side of the axle housing. Since it is configured, the lubricating oil in the oil reservoir can be smoothly discharged from the outer peripheral side, not the inner peripheral side of the axle housing, through the lubricating oil discharge part, and the lubricating oil in the oil reservoir can be circulated efficiently. Can do.

  Therefore, it is possible to prevent used lubricating oil having a high oil temperature from remaining in the oil reservoir, and to supply new lubricating oil having a low oil temperature to the bearing provided between the axle housing and the wheel mounting cylinder. The lubricating oil discharged from the oil reservoir is, for example, on the supply side of the lubricating oil provided outside the travel drive device, for example, using a filter or the like to remove foreign matters such as metal powder and wear powder, as well as a cooler, etc. The lubricating oil after cooling using can be supplied again toward the speed reduction mechanism or the like. As a result, fresh lubricating oil can be continuously supplied to the speed reduction mechanism and the bearing, and durability and life of the speed reduction mechanism and the bearing can be improved.

  According to the second aspect of the present invention, the ring gear of the planetary gear speed reduction mechanism at the final stage is formed with an inner diameter dimension close to the outer diameter dimension of the bearing, thereby reducing the outer diameter dimension of the bearing to the inner diameter (inner diameter of the wheel mounting cylinder). It is possible to form with a size close to the (circumferential surface), and to reduce a step or the like existing on the inner peripheral surface of the wheel mounting cylinder. As a result, the lubricating oil in the oil reservoir can be well guided toward the bearing side along the inner peripheral surface of the wheel mounting cylinder, and this lubricating oil can be smoothly passed from the lubricating oil discharge part to the outside of the wheel mounting cylinder. Can be discharged.

  According to the invention described in claim 3, since the guide surface made of, for example, a tapered inclined surface is formed on the inner peripheral surface of the wheel mounting cylinder, lubrication is provided between the axle housing and the wheel mounting cylinder. It is possible to prevent the oil from being retained by the guide surface, and it is possible to improve the performance of discharging the lubricating oil discharged from the lubricating oil discharge portion to the outside of the wheel mounting cylinder.

  On the other hand, according to the invention described in claim 4, since the cylindrical spindle of the axle housing accommodates a part of the speed reduction mechanism on the inner peripheral side thereof, the axial length (full length) of the entire travel drive device can be reduced. It can be shortened, and the entire apparatus can be reduced in size and weight. The cylindrical spindle of the axle housing is provided with an annular seal mounting body that seals the space between the wheel mounting cylinder and the wheel mounting cylinder via a seal member, and the seal mounting body has a lower side than the cylindrical spindle. Since the lubricating oil discharge portion is configured by providing a discharge pipe at the position, the seal member prevents the lubricating oil in the oil reservoir from leaking between the non-rotating cylindrical spindle and the rotating wheel mounting cylinder. Therefore, the lubricating oil can be smoothly discharged to the outside of the wheel mounting cylinder via the discharge pipe.

  In the invention according to claim 5, since the carrier of the planetary gear speed reduction mechanism is provided in the axle housing in a non-rotating state, the support pin that rotatably supports the planetary gear is held in the non-rotating state together with the carrier. And the lubricating oil conduit can be stably connected to the support pin. Further, such support pins are arranged around the sun gear at regular intervals and form the center of rotation of each planetary gear. Therefore, the lubricating oil supplied from the conduit into the oil path of the support pin is used as the planetary gear. Lubricating oil that can be sprayed radially by the action of centrifugal force associated with the rotation of the gear, such as a meshing surface between a planetary gear and a sun gear, a meshing surface between a planetary gear and a ring gear, etc. Can be supplied almost evenly.

  Thereby, the lubricating oil can be efficiently supplied to the planetary gear reduction mechanism, and the durability and life of each component (gear) of the planetary gear reduction mechanism can be improved. The lubricating oil supplied to the meshing surface of the sun gear and the planetary gear is stored in the oil sump by natural fall, and can lubricate, for example, the tooth surface (meshing surface) of the ring gear, and rotate the wheel mounting cylinder. The bearings and the like can be kept in a lubricated state between the non-rotating axle housing.

  Hereinafter, a dump truck traveling drive apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking a rear-wheel drive type dump truck as an example.

  Here, FIG. 1 to FIG. 9 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a dump truck employed in the present embodiment. The dump truck 1 includes a vehicle body 2 having a sturdy frame structure as shown in FIG. 1, and a loading platform mounted on the vehicle body 2 so as to be undulated. And the vessel 3 as a whole.

  The vessel 3 is formed as a large container having a total length of 10 to 13 m (meters) in order to load a large amount of heavy loads such as crushed stones, and its rear bottom is pinned to the rear end side of the vehicle body 2. It is connected via a connecting part 4 or the like so as to be able to undulate (tilt). Further, on the upper front side of the vessel 3, a flange 3 </ b> A that covers a cabin 5 described later from above is integrally provided.

  A cabin 5 is provided at the front of the vehicle body 2 and is located below the flange 3A. The cabin 5 forms a driver's cab in which a driver of the dump truck 1 gets on and off, and a driver's seat is provided in the cabin. A start switch, an accelerator pedal, a brake pedal, a steering handle, a plurality of operation levers (all not shown), and the like are provided.

  The flange portion 3A of the vessel 3 covers the cabin 5 almost completely from the upper side, thereby protecting the cabin 5 from, for example, rocks and the like, and also in the cabin 5 when the vehicle (dump truck 1) falls. It has a function to protect the driver.

  6 and 6 are left and right front wheels rotatably provided on the front side of the vehicle body 2, and each front wheel 6 constitutes a steering wheel that is steered (steered) by the driver of the dump truck 1. It is. And the front wheel 6 is formed with the tire diameter (outside diameter dimension) which extends to 2-4 m like the rear wheel 7 mentioned later, for example.

  Reference numerals 7 and 7 denote left and right rear wheels rotatably provided on the rear side of the vehicle body 2. The rear wheels 7 constitute drive wheels of the dump truck 1, and will be described later with reference to FIG. 11 is driven to rotate integrally with the wheel mounting cylinder 19. The rear wheel 7 is detachably fitted to two tires 7A and 7A, rims 7B and 7B disposed inside the tires 7A, and an rim 7B on the axially outer side of the rims 7B. And a wheel cap 7C (see FIG. 3) provided in combination.

  Reference numeral 8 denotes an engine as a prime mover provided in the vehicle body 2 at the lower side of the cabin 5. The engine 8 is composed of, for example, a large diesel engine or the like, and an alternator 9 as a generator as shown in FIG. Is to drive. The engine 8 also has a function of rotating and driving a hydraulic pump (not shown) serving as a hydraulic source, and supplying and discharging pressure oil to a later-described hoisting cylinder 73, a power steering steering cylinder (not shown), and the like. Have.

  Reference numeral 10 denotes an electric controller that constitutes a control device for the dump truck 1. The electric controller 10 is configured by a switchboard or the like that is positioned on the rear side of the cabin 5 and is erected on the vehicle body 2 as shown in FIG. Yes. The electric controller 10 charges a battery (not shown) with electricity generated by the alternator 9 shown in FIG. 2 and outputs this electricity to an electric motor 17 to be described later. It has a function for feedback control.

  Reference numeral 11 denotes a travel drive device provided on the rear wheel 7 side of the dump truck 1, and the travel drive device 11 includes an axle housing 12, an electric motor 17, a wheel mounting cylinder 19, a speed reduction mechanism 24, and the like, which will be described later. . The travel driving device 11 decelerates the rotation of the electric motor 17 by the speed reduction mechanism 24 and travels and drives the rear wheel 7 as a driving wheel of the vehicle together with the wheel mounting cylinder 19 with a large rotational torque.

  Reference numeral 12 denotes an axle housing for the rear wheel 7 provided on the rear side of the vehicle body 2. The axle housing 12 is a cylindrical body extending in the axial direction between the left and right rear wheels 7, 7, as shown in FIG. It is formed as. The axle housing 12 is provided on an intermediate suspension cylinder 13 attached to the rear side of the vehicle body 2 via a shock absorber (not shown) such as a shock absorber, and on both the left and right sides of the suspension cylinder 13. The motor housing cylinder 14 and the cylindrical spindle 15 which will be described later are configured.

  Reference numerals 14 and 14 denote motor accommodating cylinders as drive source accommodating portions provided at both ends of the suspension cylinder 13, and each of the motor accommodating cylinders 14 is formed as a cylindrical body having a tapered shape as shown in FIGS. The large diameter portion 14A side is detachably fixed to the suspension cylinder 13 shown in FIG. 2 using bolts or the like. Further, as shown in FIGS. 5 and 7, a cylindrical spindle 15 (described later) is detachably fixed to the motor accommodating cylinder 14 via a bolt 16 or the like as shown in FIGS. It is a reduction gear housing space A.

  An electric motor 17 (to be described later) serving as a drive source for the rear wheels 7 is accommodated in the motor accommodating cylinder 14. An annular partition plate 14 </ b> C is provided between the motor housing cylinder 14 and the electric motor 17, and the partition plate 14 </ b> C is provided with lubricating oil 100 in an oil reservoir 43 described later. It suppresses leakage to the surroundings.

  Reference numeral 15 denotes a cylindrical spindle that constitutes the opening on the front end side of the axle housing 12, and the cylindrical spindle 15 is composed of a large-diameter stepped cylindrical body having an inner diameter of, for example, about 80 to 100 cm. As shown in FIGS. 4, 5, and 7, the first reduction gear housing space A for housing the first stage planetary gear speed reduction mechanism 25 is formed. The outer peripheral surface of the cylindrical spindle 15 is configured to rotatably support a wheel mounting cylinder 19 on the rear wheel 7 side through bearings 20 and 21 described later.

  Here, an annular convex portion 15A that protrudes radially inward from the inner peripheral surface of the cylindrical spindle 15 is formed integrally with the intermediate portion in the axial direction. The carrier 30 is fixedly attached. The cylindrical spindle 15 has a connecting portion 15B that is connected to the motor housing cylinder 14 via a bolt 16 or the like on one side in the axial direction (base end side), and on the other side (tip side) in the axial direction, As shown in FIGS. 7 and 8, an annular flange portion 15 </ b> C protruding outward in the radial direction is integrally formed.

  A final stage carrier 39 to be described later is fixedly attached to the flange portion 15C of the cylindrical spindle 15. In this case, the outer peripheral side of the flange portion 15C is the largest outer diameter portion having the largest outer diameter dimension in the cylindrical spindle 15, and the outer diameter of the flange portion 15C is the outer diameter dimension D1 (see FIG. 8) or smaller than the outer diameter D1.

  Further, as shown in FIG. 8, an oil hole 15D extending through the annular protrusion 15A forward and rearward (in the axial direction) is formed at the lower position of the cylindrical spindle 15. Then, the lubricating oil 100 supplied into the cylindrical spindle 15 as described later can flow through the oil hole 15D before and after the annular convex portion 15A (in the axial direction of the cylindrical spindle 15).

  The cylindrical spindle 15 is assembled as a covered cylindrical body having a sturdy structure by being fixedly provided with the carriers 30 and 39 of the planetary gear speed reduction mechanisms 25 and 34 as described later. The mounting cylinder 19 (rear wheel 7) can be supported from the inside with high rigidity (strength). The cylindrical spindle 15 has a function of receiving a rotational reaction force generated in planetary gear speed reduction mechanisms 25 and 34, which will be described later, with sufficient strength via the carriers 30 and 39.

  Here, the first reduction gear housing space A is surrounded by the motor housing cylinder 14 and the cylindrical spindle 15 as shown in FIGS. 5 and 7, and one side (inner side) in the axial direction thereof is a partition plate 14C and an electric motor described later. The motor 17 is closed, and the other side (outside) in the axial direction is covered with a coupling 33 and the like which will be described later. In the reduction gear housing space A, a first-stage planetary gear speed reduction mechanism 25 described later is housed.

  Reference numeral 17 denotes an electric motor as a drive source which is detachably provided on the motor housing cylinder 14 of the axle housing 12, and the electric motor 17 rotates the left and right rear wheels 7, 7 independently of each other as shown in FIG. For driving, they are mounted in left and right motor housing cylinders 14 and 14 located on both sides of the axle housing 12, respectively.

  The electric motor 17 has a rotary shaft 18 extending in the axial direction from the motor housing cylinder 14 toward the reduction gear housing space A in the cylindrical spindle 15 as shown in FIGS. 4 and 5. 18 is rotationally driven by the electric motor 17 in the forward or reverse direction. A sun gear 26 (described later) is splined to the distal end side of the rotary shaft 18 so as to rotate integrally.

  Reference numeral 19 denotes a wheel mounting cylinder that rotates integrally with the rear wheel 7 as a wheel. The wheel mounting cylinder 19 constitutes a so-called wheel hub, and rims 7B and 7B of the rear wheel 7 are press-fitted on the outer peripheral side thereof. It is detachably attached using means. The wheel mounting cylinder 19 includes a one-side cylinder portion 19A extending in the axial direction between the bearings 20 and 21, and an end surface of the one-side cylinder portion 19A extending in the axial direction toward a ring gear 36 to be described later. 19B1 is formed as a stepped cylindrical body by the other side cylinder part 19B formed with an inner diameter larger than the one side cylinder part 19A.

  In addition, the one side cylinder portion 19A of the wheel mounting cylinder 19 is provided with bearing mounting portions 19C and 19D on the inner peripheral side thereof, with bearings 20 and 21 (described later) fitted and attached as steps. Further, on the inner peripheral side of the one-side cylinder portion 19A, the retainer 63 of the seal device 60 described later is attached, which is located between the end surface on the one side in the axial direction and the bearing attachment portion 19C and expands in a tapered shape. A retainer mounting portion 19E as an expanding portion is formed.

  Here, the other side cylinder portion 19B of the wheel mounting cylinder 19 has an inner peripheral surface 19B1 having an inner diameter substantially equal to an inner diameter D2 of a disk holding cylinder 22 described later. And the other side cylinder part 19B surrounds the collar part 15C etc. of the cylindrical spindle 15 from a radial direction outer side, and permits the lubricating oil 100 to distribute | circulate from the reduction gear accommodation space B mentioned later toward the annular space C. It is.

  A ring gear 36 (discussed below) and a disc holding cylinder 22 for the disc 22A are integrally fixed to the other side cylinder portion 19B of the wheel mounting cylinder 19 using a long bolt 23 (see FIG. 6). Thus, the wheel mounting cylinder 19 is rotated integrally with the ring gear 36. That is, the wheel mounting cylinder 19 is transmitted via the ring gear 36 the rotation that has become a large torque by decelerating the rotation of the electric motor 17 by the speed reduction mechanism 24. And the wheel attachment cylinder 19 rotates the rear wheel 7 used as a driving wheel of a vehicle with a large rotational torque.

  In this case, the inner peripheral side of the wheel mounting cylinder 19, the disk holding cylinder 22, and the ring gear 36 is formed as a second speed reducer accommodation space B in which a second stage planetary gear speed reduction mechanism 34 described later is accommodated. The second reduction gear housing space B is surrounded by a coupling 33 and the like, which will be described later, with the first reduction gear housing space A located on the one side in the axial direction. Is covered with a carrier 39, an inner cap 42, a seal device 71 and the like, which will be described later.

  The space between the wheel mounting cylinder 19 and the cylindrical spindle 15 is an annular space C that annularly surrounds the outer peripheral side of the cylindrical spindle 15, and the lubricating oil 100 is accommodated in the lower part of the annular space C. Is. The annular space C is always in communication with the second reduction gear housing space B through a gap in the bearing 21 and the like.

  Further, the one side cylinder portion 19A of the wheel mounting cylinder 19 has an inner circumferential surface located between the bearing mounting sections 19C and 19D gradually from the bearing 21 side to the bearing 20 side as shown in FIGS. It is formed as a tapered guide surface (hereinafter referred to as an inclined surface 19F) that expands in diameter, and the lubricating oil 100 in the annular space C is guided toward the later-described discharge pipe 69 by the inclined surface 19F. . On the one side (inner side) in the axial direction of the wheel mounting cylinder 19, a seal device 60 described later is provided at a position between the motor housing cylinder 14 of the axle housing 12, the cylindrical spindle 15 and the wheel mounting cylinder 19. It has been.

  Reference numerals 20 and 21 denote bearings that rotatably support the wheel mounting cylinder 19 on the outer peripheral side of the cylindrical spindle 15, and the bearings 20 and 21 are configured using, for example, the same tapered roller bearing or the like. Between the one side cylinder portion 19 </ b> A and the cylindrical spindle 15, it is disposed so as to be separated in the axial direction. That is, one bearing 20 is fitted and mounted in a bearing mounting portion 19C of the wheel mounting cylinder 19, and the other bearing 21 is fitted and mounted in a bearing mounting portion 19D of the wheel mounting cylinder 19. Yes.

  The outer diameter D1 of the bearings 20 and 21 (the inner diameter of the bearing mounting portions 19C and 19D) is larger than the inner diameter of the one side cylinder portion 19A as shown in FIG. 8, and the inner diameter (described later) of the other side cylinder portion 19B. It is formed smaller than the inner diameter D2) of the disc holding cylinder 22 to be performed.

  Further, the outer diameter D1 of the bearings 20 and 21 is formed to be larger than the maximum outer diameter of the carrier 39 in the final stage (second stage) described later, and the inner diameter D4 (see FIG. 8) of the ring gear 36 in the final stage. Close dimensions are formed. The outer diameter D1 of the bearings 20 and 21 is formed to be larger than the inner diameter of the ring gear 36 (the inner diameter D4 of the inner teeth 36A shown in FIG. 8) as will be described later.

  Reference numeral 22 denotes a disk holding cylinder that constitutes a part of the wheel mounting cylinder 19 together with the ring gear 36. The disk holding cylinder 22 sandwiches the ring gear 36 at a position on the outer side in the axial direction of the wheel mounting cylinder 19 as shown in FIG. It attaches and is detachably fixed (integrated) to the wheel mounting cylinder 19 using a plurality of long bolts 23, 23,... Shown in FIG.

  As shown in FIG. 6, a ring-shaped (annular) disk 22 </ b> A is secured to the disk holding cylinder 22 and attached in a non-rotating state. The disk 22 </ b> A is given a braking force by a disk brake 56 described later. Is done. That is, the rear wheel 7 and the wheel mounting cylinder 19 rotate integrally with the disk holding cylinder 22 and the disk 22A, and the rotation during running is stopped (braking) by the braking force applied to the disk 22A.

  In this case, the inner diameter D2 of the disk holding cylinder 22 is formed to have an inner diameter dimension substantially equal to that of the other cylinder portion 19B (inner peripheral surface 19B1) of the wheel mounting cylinder 19 as shown in FIG. The inner diameter D2 of the other side cylinder portion 19B and the disc holding cylinder 22 is set to have a relationship according to the following formula 1 with respect to the outer diameter D1 of the bearings 20 and 21.

  The radial dimension D3 of the inner tooth 36A is the height dimension between the root and the tooth tip of the inner tooth 36A, and the inner diameter D2 of the disc holding cylinder 22 and the inner diameter D4 of the ring gear 36 shown in FIG. On the other hand, the relationship of the following formula 2 is satisfied.

  Reference numeral 24 denotes a speed reduction mechanism provided between the cylindrical spindle 15 and the wheel mounting cylinder 19, and the speed reduction mechanism 24 includes a first stage planetary gear speed reduction mechanism 25 and a second stage planetary gear speed reduction mechanism 34, which will be described later. The rotation of the rotary shaft 18 is decelerated and transmitted to the wheel mounting cylinder 19 on the rear wheel 7 side.

  Reference numeral 25 denotes a first stage planetary gear reduction mechanism which is a carrier fixed type and is provided in the cylindrical spindle 15 of the axle housing 12. The planetary gear reduction mechanism 25 is shown in FIGS. 4, 5, 7 and 8. As shown, for example, three planetary gears that mesh with the sun gear 26 splined to the tip end of the rotating shaft 18 and the sun gear 26 and the internal teeth 27A of the ring gear 27 and rotate according to the rotation of the sun gear 26. 28 (only one is shown) and a carrier 30 that rotatably supports each planetary gear 28 via a support pin 29.

  The first stage carrier 30 is fixed to the annular convex portion 15A of the cylindrical spindle 15 in a non-rotating state and detachably using a bolt 31 (see FIG. 8) or the like. It is accommodated in the reducer accommodating space A of the cylindrical spindle 15 together with 28 and the like. Further, on the inner peripheral side of the carrier 30, as shown in FIG. 8, a bearing 32 that rotatably supports the tip end side of the rotating shaft 18 is provided.

  The first stage ring gear 27 is formed as a short cylindrical gear that surrounds the sun gear 26, the planetary gear 28, the support pin 29, the carrier 30, and the like from the outside in the radial direction, and is formed on the inner peripheral side of the cylindrical spindle 15. It arrange | positions so that relative rotation is possible via a small radial gap (for example, about 2-5 mm). Then, on the inner peripheral side of the ring gear 27, internal teeth 27A (see FIG. 8) that mesh with the planetary gears 28 are formed.

  Here, in the first stage planetary gear speed reduction mechanism 25, the revolution of the planetary gear 28 (rotation of the carrier 30) is restrained by fixing the carrier 30 to the cylindrical spindle 15. Then, when the sun gear 26 is integrally rotated by the rotating shaft 18 of the electric motor 17, the first stage planetary gear reduction mechanism 25 converts the rotation of the sun gear 26 into the rotation of the plurality of planetary gears 28.

  The planetary gear speed reduction mechanism 25 in the first stage takes out the rotation (rotation) of each planetary gear 28 as a reduced speed rotation of the ring gear 27 and rotates the rotation of the ring gear 27 through the coupling 33 described later to the second stage. Is transmitted to the planetary gear speed reduction mechanism 34.

  Further, as shown in FIG. 8, an oil passage 29A for supplying the lubricating oil 100 is formed in the support pin 29 of each planetary gear 28. The oil passage 29A is formed in the cylindrical spindle 15 in the axial direction. An after-mentioned conduit 45 extending is connected. Then, the lubricating oil 100 guided from the conduit 45 into the oil passage 29A is supplied so as to be injected toward the bearings 28A of the planetary gear 28, and the tooth surfaces of the bearings 28A and the planetary gear 28 are lubricated. It is something to keep in.

  Further, the carrier 30 of the planetary gear reduction mechanism 25 is provided with an oil passage 30A indicated by a dotted line in FIGS. 7 and 8, for example, at a position spaced apart from the planetary gear 28 in the circumferential direction. The branch pipe 49 and the conduit 50 are communicated with each other before and after the carrier 30. The carrier 30 is also provided with a fluid hole (not shown) through which brake fluid pressure flows between brake pipes 53 and 54 described later.

  Reference numeral 33 denotes a coupling as a rotation transmitting member that rotates integrally with the first stage ring gear 27, and the coupling 33 is provided between the first stage planetary gear reduction mechanism 25 and the second stage planetary gear reduction mechanism 34. The outer peripheral side is coupled to the first stage ring gear 27 by means such as a spline.

  Further, the inner peripheral side of the coupling 33 is coupled to a second stage sun gear 35 described later by means such as a spline. The coupling 33 transmits the rotation of the first-stage ring gear 27 to the second-stage sun gear 35 and rotates the sun gear 35 integrally with the ring gear 27 at the same speed. The coupling 33 has a plurality of oil holes through which the lubricating oil 100 in the first reduction gear housing space A flows toward the second reduction gear housing space B before and after the coupling 33 (see FIG. (Not shown) may be formed.

  Reference numeral 34 denotes a second-stage planetary gear reduction mechanism that is the final stage employed in the present embodiment, and the planetary gear reduction mechanism 34 is disposed between the cylindrical spindle 15 and the wheel mounting cylinder 19 in the first-stage planetary gear. It is arranged via a speed reduction mechanism 25 and, together with the first stage planetary gear speed reduction mechanism 25, reduces the rotation of the rotary shaft 18 and generates a large rotational torque in the wheel mounting cylinder 19.

  In this case, the planetary gear speed reduction mechanism 34 at the second stage is arranged so as to be coaxial with the rotary shaft 18 and rotates integrally with the coupling 33, and the internal teeth 36 </ b> A of the sun gear 35 and the ring gear 36. (See FIG. 8) and, for example, three planetary gears 37 (only one is shown) that rotate according to the rotation of the sun gear 35, and each planetary gear 37 is rotatably supported via a support pin 38. It is comprised by the carrier 39 grade | etc.,.

  The second stage carrier 39 is fixed to the flange 15C of the cylindrical spindle 15 in a non-rotating state and detachably using a bolt 40 (see FIG. 8) or the like. As a result, the carrier 39 also serves as a lid that covers the reduction gear housing space A from the outside at the open end of the cylindrical spindle 15. Further, as shown in FIG. 8, a bearing 41 and the like are provided on the inner peripheral side of the carrier 39, and this bearing 41 supports the sun gear 35 so as to be rotatable from both sides in the axial direction with the coupling 33. Yes.

  On the other hand, the second-stage ring gear 36 is formed as a short cylindrical body that surrounds the sun gear 35, the planetary gear 37, the support pin 38, the carrier 39 and the like from the outside in the radial direction, and the wheel mounting cylinder 19 and the disk holding cylinder 22. And are integrally fixed to each other. Further, on the inner peripheral side of the ring gear 36, internal teeth 36A (see FIG. 8) that mesh with the planetary gears 37 are formed.

  Further, the inner diameter of the ring gear 36 (the inner diameter D4 of the inner teeth 36A) is close to the outer diameter dimension D1 of the bearing 21 shown in FIG. 8 and is smaller than the outer diameter dimension D1 (D4 ≦ D1). Is. The radial dimension D3 (height dimension of the internal tooth 36A) between the root and the tip of the internal tooth 36A is, for example, about 10 to 20 mm so as to satisfy the above-mentioned formula 1 and formula 2. Set to dimensions.

  Here, in the second stage planetary gear speed reduction mechanism 34 as the final stage, the revolution of the planetary gear 37 (rotation of the carrier 39) is restrained by fixing the carrier 39 to the cylindrical spindle 15. Then, when the sun gear 35 rotates together with the coupling 33, the planetary gear speed reduction mechanism 34 at the second stage converts the rotation of the sun gear 35 into the rotation of the plurality of planetary gears 37, and this rotation (rotation). Is taken out from the ring gear 36 as a reduced speed rotation.

  That is, the ring gear 36 in this case is provided integrally with the wheel mounting cylinder 19 together with the disk holding cylinder 22. The wheel mounting cylinder 19 on the side of the rear wheel 7 is transmitted with a large output rotational torque reduced in two stages by the first stage planetary gear reduction mechanism 25 and the second stage planetary gear reduction mechanism 34. It is.

  Further, as shown in FIG. 8, an oil passage 38 </ b> A is formed in the support pin 38 of each planetary gear 37, and a later-described supply pipe 51 is connected to the oil passage 38 </ b> A from the outside of the carrier 39. Then, the lubricating oil 100 guided from the supply pipe 51 into the oil passage 38A is supplied so as to be injected toward the bearings 37A of the planetary gears 37, and the tooth surfaces of the bearings 37A and the planetary gears 37 are lubricated. It is something to keep in.

  On the other hand, the carrier 39 of the planetary gear speed reduction mechanism 34 is formed with an oil groove 39A extending upward and downward along the flange portion 15C of the cylindrical spindle 15 as shown in FIG. The radially inner side and the outer side of the carrier 39 are always in communication with each other through the oil groove 39A, and the lubricating oil 100 supplied into the first and second reduction gear housing spaces A and B is in the oil groove 39A. It distribute | circulates toward the position which becomes the lower side of the wheel attachment cylinder 19 via.

  Reference numeral 42 denotes an inner cap that covers the inner peripheral side of the carrier 39. The inner cap 42 is detachably provided on the inner peripheral side of the carrier 39 via a bolt or the like as shown in FIG. The carrier 39 is held in a retaining state. The inner cap 42 covers the opening end side of the cylindrical spindle 15 together with the carrier 39 to prevent the lubricating oil 100 and the like in the second reduction gear housing space B from leaking from the inside of the carrier 39. is there.

  43 is an oil sump provided inside the cylindrical spindle 15 and the wheel mounting cylinder 19, and this oil sump 43 is provided below the first and second reduction gear housing spaces A and B and the annular space C described above. The lubricating oil 100 formed at the position and supplied to the speed reduction mechanism 24 is accommodated at, for example, the liquid level shown in FIG. In this case, the lubricating oil 100 in the oil reservoir 43 is set at a liquid level lower than the central axis (the conduit 45 described later) of the planetary gear 28 and the support pin 29.

  As a result, the lubricating oil 100 in the oil reservoir 43 is subjected to rotational resistance (rotation due to the viscous resistance of the lubricating oil) applied to the ring gears 27 and 36 of the planetary gear reduction mechanisms 25 and 34, the planetary gears 28 and 37 that rotate, the coupling 33, and the like. Load) is kept small, and the bearings 20, 21 and the ring gears 27, 36 are always kept in a lubrication state.

  Reference numeral 44 denotes a first lubricating oil supply section provided in the axle housing 12. The lubricating oil supply section 44 includes a conduit 45 extending in the axial direction in the cylindrical spindle 15 and a support pin 29 of each planetary gear 28. And the oil passage 29A and the like formed inside. One side (base end side) of the conduit 45 is connected to a lubricating oil supply pipe 46 at the position of the partition plate 14 </ b> C shown in FIG. 7, and this supply pipe 46 is a vehicle-mounted vehicle that serves as a supply source of the lubricating oil 100. It is connected to a lubricating oil pump (not shown).

  Further, the other side (tip side) of the conduit 45 is connected to an oil passage 29A of the support pin 29, and in this oil passage 29A, the lubricating oil discharged from the lubricating oil pump is connected to the supply pipe 46 and the conduit 45. Led through. The lubricating oil 100 in the oil passage 29A is supplied so as to be injected toward the bearings 28A of the planetary gear 28, and the tooth surfaces of the bearings 28A and the planetary gear 28 are kept in a lubrication state.

  Note that a plurality of (for example, three) planetary gears 28 are attached to the first stage carrier 30 via support pins 29, and other planetary gears 28 not shown in FIG. Lubricating oil is similarly supplied from a midway position of the conduit 45 through a branch pipe (not shown) branched by a joint 48 described later.

  47 is a second lubricating oil supply section for supplying the lubricating oil 100 to the planetary gear reduction mechanism 34 in the second stage, and this lubricating oil supply section 47 is connected to the joint 48 from the middle of the conduit 45 as shown in FIG. A branch pipe 49 branched via the oil pipe, the oil passage 30A of the carrier 30 to which the distal end side of the branch pipe 49 is connected, and a lubricating oil conduit 50 connected to the branch pipe 49 via the oil passage 30A. And a supply pipe 51 described later.

  Here, as shown by a two-dot chain line in FIG. 8, the lubricating oil conduit 50 extends in the axial direction inside the second-stage sun gear 35 with a gap, and the tip side thereof is attached to the inner cap 42. A supply pipe 51 (described later) is connected to the end of the conduit 50 drawn out from the inner cap 42. Further, the proximal end side of the conduit 50 is connected to the branch pipe 49 via the oil passage 30A or the like drilled in the first stage carrier 30 as described above.

  51 are supply pipes as other conduits for supplying the lubricating oil 100 to the second stage planetary gear speed reduction mechanism 34. These supply tubes 51 are outside the carrier 39 as shown in FIG. It is connected to an oil passage 38A (see FIG. 8) of each support pin 38 at a position. Further, these supply pipes 51 are connected to a conduit 50 and the like indicated by a two-dot chain line in FIG. 8, and lubricating oil is supplied from the branch pipe 49 side. The lubricating oil 100 is supplied in an injection state into the oil passages 38 </ b> A of the support pins 38 through the supply pipes 51.

  52 is a return pipe provided outside the inner cap 42. This return pipe 52 is connected to the most downstream side of the supply pipe 51 as shown in FIG. As shown in FIG. 8, it returns to the inside of the inner cap 42. The return oil (lubricating oil) is supplied to the bearing 41 and the like between the inner cap 42 and the sun gear 35, and then gradually falls and stored in the oil reservoir 43.

  A brake pipe 53 is disposed in the cylindrical sun gear 35 with a gap and extends in the axial direction. Like the lubricating oil conduit 50, the brake pipe 53 is attached to the inner cap 42 from the inner cap 42. Has been pulled out. Further, the base end side (one side) of the brake pipe 53 extends toward the first-stage carrier 30, and the other through the above-described liquid hole (not shown) drilled in the first-stage carrier 30. The brake pipe 54 is connected.

  Further, as shown in FIG. 5, the other brake pipe 54 extends in the axial direction in the reduction gear housing space A of the cylindrical spindle 15, and the base end side thereof includes a brake hydraulic pressure control valve mounted on the vehicle. Via a master cylinder (not shown). When the brake is operated, the brake fluid pressure from the master cinder is supplied from the brake pipe 54 toward the brake pipe 53.

  Further, the tip end side of the brake pipe 53 drawn out from the inner cap 42 is connected to a total of three branch pipes 55, 55,... (See FIG. 6) made of, for example, a flexible hose. These branch pipes 55 supply the brake fluid pressure from the brake pipe 53 side to each disk brake 56 described later.

  56, 56,... Are a plurality of disc brakes that constitute a brake means together with the disc 22A, and each disc brake 56 is externally (decelerated) in the axial direction to the second stage carrier 39 as shown in FIG. It is attached using bolts 57 or the like from outside the machine housing space A). Further, a total of three disc brakes 56 are provided at intervals in the circumferential direction of the disc 22A as shown in FIG.

  The disc brake 56 receives the brake fluid pressure from the master cylinder via the brake pipes 54, 53 and the branch pipes 55, so that the disc 22A is clamped from both sides in the axial direction. A braking force is applied to the wheel mounting cylinder 19 (rear wheel 7) that rotates integrally.

  58 is a drain hole formed in the lowermost part of the wheel mounting cylinder 19, and the drain hole 58 extends in the axial direction through the ring gear 36 and the disk holding cylinder 22 as shown in FIG. The plug 59 is detachably closed. When the plug 59 is removed, the lubricating oil 100 accumulated in the oil reservoir 43 (the wheel mounting cylinder 19) can be discharged to the outside through the drain hole 58.

  Reference numeral 60 denotes a sealing device that seals the space between the cylindrical spindle 15 and the wheel mounting cylinder 19 in a liquid-tight manner. The sealing device 60 is constituted by a so-called floating seal as shown in FIGS. 5, 7, and 9. . The sealing device 60 prevents the lubricating oil 100 accommodated in the annular space C between the cylindrical spindle 15 and the wheel mounting cylinder 19 from leaking to the outside of a retainer 61 described later, and earth and sand, rainwater, etc. Intrusion into the annular space C is prevented.

  Here, as shown in FIG. 9, the sealing device 60 includes a fixed-side retainer 61 sandwiched between the motor housing cylinder 14 of the axle housing 12 and the cylindrical spindle 15 via a bolt 16 and the like, and a wheel mounting cylinder. A retainer 63 on the rotating side that is located in the retainer mounting portion 19E of 19 and is attached to an end face on one axial side via a bolt 62 or the like, and a pair of O as a seal member between these retainers 61, 63 The ring 64 is composed of a pair of seal rings 65 and 65 disposed so as to be opposed to each other in the axial direction.

  The seal device 60 elastically deforms the pair of O-rings 64 between the retainers 61 and 63 and the seal rings 65 and 65, seals between the retainers 61 and 63 and the respective O-rings 64, and An axial pressing force is applied to each seal ring 65 with 64 elastic restoring force. As a result, the pair of seal rings 65, 65 come into sliding contact with each other in the axial direction, and seal the sliding contact surfaces of both in a liquid-tight manner.

  Further, as shown in FIG. 9, the retainer 61 on the fixed side is a cylindrical portion 61A fitted on the outer peripheral side of the cylindrical spindle 15, and projects from the base end side of the cylindrical portion 61A inward in the radial direction, and is a motor housing cylinder. 14 and an annular protrusion 61B sandwiched between the cylindrical spindle 15 and an annular flange portion 61D that protrudes radially outward from the proximal end side of the cylindrical portion 61A and is integrally formed with a holding portion 61C of an O-ring 64. It is comprised by.

  An annular protrusion 61B of the retainer 61 has a shim plate, which will be described later, on an end surface on one axial side (base end side) of the cylindrical spindle 15 when the cylindrical portion 61A is fitted to the outer peripheral side of the cylindrical spindle 15. 67, and is fixed to the end surface side of the cylindrical spindle 15 by a bolt 66. The retainer 61 constitutes a seal attachment body that is a part of a lubricating oil discharge portion 68 described later, and a discharge tube 69 described later is connected to the flange portion 61D.

  Reference numeral 67 denotes a shim plate sandwiched between a stationary retainer 61 and the cylindrical spindle 15 using a bolt 66, and the shim plate 67 extends in the circumferential direction along the proximal end surface of the cylindrical spindle 15. It is formed as an annular flat plate. And the shim board 67 adjusts the space | interval S (refer FIG. 9) between the annular protrusion 61B of the retainer 61 and the end surface of the cylindrical spindle 15 according to the board thickness or the number of sheets.

  In this case, the cylindrical portion 61A of the retainer 61 fitted to the outer peripheral side of the cylindrical spindle 15 is in contact with the inner ring of the bearing 20 at the tip end side, and the axial set load (thrust load) on the bearing 20 is applied to the shim plate. It is variably adjusted according to the thickness or the number of sheets. Further, the other bearing 21 disposed between the cylindrical spindle 15 and the wheel mounting cylinder 19 is also in contact with the flange 15C side of the cylindrical spindle 15 as shown in FIG. The set load (thrust load) of the bearing 21 is variably adjusted according to the thickness or number of shim plates 67.

  Reference numeral 68 denotes a lubricating oil discharge portion that sucks and discharges the lubricating oil 100 in the oil reservoir 43 to the outside of the wheel mounting cylinder 19, and the lubricating oil discharge portion 68 is connected to the flange portion 61 </ b> D of the retainer 61, which will be described later. 69 is connected and provided.

  Reference numeral 69 denotes a lubricating oil discharge pipe provided in connection with the flange portion 61D of the retainer 61. The discharge pipe 69 is located at the lowest position between the cylindrical spindle 15 and the wheel mounting cylinder 19. For example, the lubricating oil 100 supplied as described above into the first and second reduction gear housing spaces A and B and the annular space C and stored in the oil reservoir 43 is replaced with the above-described on-vehicle lubricating oil pump or the like. Thus, the air is sucked and discharged toward the outside of the annular space C.

  In this case, the discharge pipe 69 is attached to the retainer 61 with one end portion serving as a suction port 69A, and this suction port 69A is equivalent to the roller (roller) of the bearing 20 below the cylindrical spindle 15. It is arranged at the height position. The discharge pipe 69 is drawn out of the axle housing 12 (motor housing cylinder 14) from the position of the suction port 69A via the retainer 61. The other end 69B, which is the downstream side of the discharge pipe 69, is attached to the large-diameter part 14A side of the motor housing cylinder 14, and other pipes, filters, and the like from the suspension cylinder 13 side of the axle housing 12 shown in FIG. It is connected to the suction side of the lubricating oil pump via a cooling device (both not shown).

  Further, a detector (not shown) for detecting the height of the lubricating oil 100 contained in the oil reservoir 43 is provided on the small diameter portion 14B side of the motor housing cylinder 14, for example. When the liquid level in the oil reservoir 43 becomes higher than a predetermined reference liquid level, the lubricating oil 100 in the oil reservoir 43 is removed from the discharge pipe 69 by the pump as indicated by an arrow D in FIGS. Force to drain in the direction.

  Accordingly, the lubricating oil 100 in the oil reservoir 43 has a liquid level illustrated in FIG. 7 (for example, a liquid level equivalent to or slightly lower than the central axis of the planetary gear 28 and the support pin 29). The lubricating oil discharged from the discharge pipe 69 is supplied to the supply pipe 46 side again after removing foreign substances with the filter and cooling with the cooling device. Is.

  70 is an air discharge pipe provided on the partition plate 14C of the motor housing cylinder 14, and the air discharge pipe 70 is attached to the upper side of the partition plate 14C as shown in FIG. Exhaust air to the outside. Thereby, the inside of the cylindrical spindle 15 and the wheel mounting cylinder 19 is always kept at a pressure equal to or lower than the atmospheric pressure.

  Reference numeral 71 denotes another seal device disposed at a position on the outer side in the axial direction of the wheel mounting cylinder 19, and the seal apparatus 71 is configured as a so-called floating seal, and as shown in FIGS. Between the last stage (second stage) carrier 39, a fixed retainer 71A is provided. This sealing device 71 is also configured in substantially the same manner as the sealing device 60 shown in FIGS. 7 and 9 arranged on one side (inside) in the axial direction of the wheel mounting cylinder 19, and in the second reduction gear housing space B. This prevents the lubricating oil 100 from leaking to the outside from between the disk holding cylinder 22 and the retainer 71A on the carrier 39 side, and prevents the entry of external earth and sand, rainwater, and the like.

  Reference numeral 72 denotes a wedge member that detachably fixes the rear wheel 7 to the outer peripheral side of the wheel mounting cylinder 19, and the wedge member 72 is arranged from the outer side in the axial direction of the wheel mounting cylinder 19 as shown in FIGS. 4 and 5. 7 is fitted between the rim 7B and the wheel mounting cylinder 19, and the rear wheel 7 is prevented from being pulled out of the wheel mounting cylinder 19 and held in a rotating state.

  For this reason, ten or more wedge members 72 are provided at intervals in the circumferential direction of the wheel mounting cylinder 19, and the rear wheel 7 is removed from the wheel mounting cylinder 19 by detaching these wedge members 72. is there. 7 to 9 show a state in which the rear wheel 7 and the wedge member 72 are removed from the outer peripheral side of the wheel mounting cylinder 19.

  73 is a hoisting cylinder for hoisting the vessel 3 of the lift truck 1 shown in FIG. 1, and the hoisting cylinder 73 is located between the front wheel 6 and the rear wheel 7 as shown in FIG. It is arranged on both the left and right sides. The hoisting cylinder 73 expands and contracts in the upward and downward directions when pressure oil is supplied and discharged from the outside, and causes the vessel 3 to hoist (tilt) around the pin coupling portion 4 on the rear side.

  Reference numeral 74 denotes a hydraulic oil tank. The hydraulic oil tank 74 is positioned below the vessel 3 and attached to the side surface of the vehicle body 2 as shown in FIG. The hydraulic oil stored in the hydraulic oil tank 74 is supplied to and discharged from the hoisting cylinder 73 and the steering cylinder for power steering as pressure oil by the hydraulic pump.

  The traveling drive device 11 of the dump truck 1 according to the present embodiment has the above-described configuration, and the operation thereof will be described next.

  First, when a driver who has entered the cabin 5 of the dump truck 1 starts the engine 8 shown in FIG. 2, a hydraulic pump (not shown) serving as a hydraulic source is rotationally driven and power is generated by the alternator 9. The electricity is supplied to the electric controller 10 and the like while the electricity is charged in the battery and the like.

  When the vehicle is driven to travel, a drive current is supplied from the electric controller 10 to each electric motor 17 on the rear wheel 7 side. At this time, the electric controller 10 determines the rotational speeds of the left and right electric motors 17 and 17. Individual feedback control. As a result, the left and right rear wheels 7 and 7 serving as drive wheels of the vehicle are driven to rotate independently of each other, and are driven at the same rotational speed when traveling straight ahead.

  That is, the traveling drive device 11 provided on the rear wheel 7 side of the dump truck 1 reduces the rotation of the electric motor 17 (rotating shaft 18) by, for example, about 30 to 40 by the multi-stage planetary gear reduction mechanisms 25 and 34. The rear wheel 7 serving as a driving wheel is driven to travel with a large rotational torque together with the wheel mounting cylinder 19. The left and right rear wheels 7 are driven by the left and right electric motors 17 at independent rotation speeds.

  Further, in the first-stage and second-stage planetary gear speed reduction mechanisms 25, 34, etc., the lubricating oil 100 discharged from the on-vehicle lubricating oil pump (supply source) passes through the supply pipe 46 shown in FIG. The oil is supplied to the oil supply unit 44 and the second lubricating oil supply unit 47, and the sun gears 26 and 35, the planetary gears 28 and 37, etc. are kept in a lubrication state. The lubricating oil 100 at this time is dripped and stored in the lower oil reservoir 43 by the action of gravity while lubricating each tooth surface and the like.

  In this case, in the first lubricating oil supply section 44, the lubricating oil 100 guided from the supply pipe 46 through the conduit 45 into the oil passage 29 </ b> A of the support pin 29 is directed toward the bearings 28 </ b> A of the planetary gears 28. Let spray. Then, each planetary gear 28 that rotates can guide the lubricating oil 100 to the outside in the radial direction by the centrifugal force due to the rotation, and keep the meshing surfaces and the like of the planetary gear 28, the sun gear 26, and the ring gear 27 in a lubricated state. it can.

  Further, in the second lubricating oil supply section 47, as illustrated in FIG. 7, the branch pipe 49 branched from the middle position of the conduit 45 via the joint 48, the oil passage 30A in the carrier 30, the conduit 50, and each supply The lubricating oil 100 introduced into the oil passage 38A of the support pin 38 through the pipe 51 (see FIG. 6) or the like is injected toward the bearings 37A of the planetary gears 37 and the like. These planetary gears 37 can guide the lubricating oil 100 to the outside in the radial direction by the centrifugal force generated by the rotation, and keep the meshing surfaces of the planetary gear 38, the sun gear 35, and the ring gear 36 in a lubricated state. .

  A return pipe 52 is connected to the most downstream side of the supply pipe 51 shown in FIG. 6, and excess lubricating oil in the supply pipe 51 is returned to the inside of the inner cap 42 by the return pipe 52. Then, the return oil (lubricating oil) is supplied to the bearing 41 and the like between the inner cap 42 and the sun gear 35 and then gradually dropped into the oil reservoir 43 and stored.

  Further, the lubricating oil 100 accommodated in the oil sump 43 is sequentially scraped upward by the internal teeth 27A, 36A, etc. of the rotating first-stage and second-stage ring gears 27, 36, and the planetary gear reduction mechanism 25. , 34 can be scraped and lubricated. The lubricating oil 100 in the annular space C can be supplied also to the bearings 20 and 21 between the cylindrical spindle 15 and the wheel mounting cylinder 19.

  On the other hand, between the cylindrical spindle 15 and the wheel mounting cylinder 19, a sealing device 60 for sealing the lubricating oil 100 is provided in the annular space C, and a retainer 61 serving as a sealing mounting body of the sealing device 60 is provided in the retainer 61. Further, a discharge pipe 69 of the lubricating oil discharge portion 68 is connected to the lowermost portion of the cylindrical spindle 15 and the wheel mounting cylinder 19. And the edge part used as the downstream of the discharge pipe 69 is connected to the suction side of the said lubricating oil pump through a filter, a cooling device (all are not shown), etc.

  In addition, the liquid level of the lubricating oil 100 contained in the oil reservoir 43 is constantly monitored using a detector or the like, and a reference liquid level (for example, FIG. When the oil level becomes higher than the liquid level shown in FIG. 7, the lubricating oil 100 in the oil reservoir 43 can be forcibly discharged from the discharge pipe 69 to the outside by the lubricating oil pump. Thereby, the lubricating oil 100 in the oil reservoir 43 is discharged to the outside of the annular space C through the discharge pipe 69, and at this time, foreign matter in the discharged oil (lubricating oil) can be filtered and removed by the filter. The lubricating oil can be cooled by the cooling device.

  By the way, in the oil reservoir 43 provided in the cylindrical spindle 15 and the wheel mounting cylinder 19, the lubricating oil 100 supplied to the speed reduction mechanism 24 and the like is gradually dropped and stored. Therefore, foreign matter such as wear powder and metal powder tends to stay, and the oil temperature of the lubricating oil 100 tends to increase.

  Therefore, according to the present embodiment, the axle housing 12 provided on the rear wheel 7 side of the vehicle is provided with the motor housing cylinder 14, the cylindrical spindle 15 provided detachably on the outside in the axial direction of the motor housing cylinder 14, and the like. The lubricating oil 100 in the oil sump 43 is sucked to the outside from the annular space C between the wheel mounting cylinder 19 and the cylindrical spindle 15 at the lower part on the outer peripheral side of the cylindrical spindle 15. Thus, a lubricating oil discharge portion 68 that discharges in the direction of arrow D is provided.

  The lubricating oil discharge portion 68 is more than the cylindrical spindle 15 with respect to the retainer 61 of the seal device 60 that seals the lubricating oil 100 in the annular space C between the cylindrical spindle 15 and the wheel mounting cylinder 19. The suction pipe 69A of the discharge pipe 69 is connected at a lower position, and the discharge pipe 69 discharges the lubricating oil 100 in the annular space C from the suction port 69A to the outside of the retainer 61. .

  Therefore, when the lubricating oil 100 in the oil reservoir 43 is sucked and discharged from the suction port 69A of the discharge pipe 69 to the outside, the lubricating oil 100 is in the annular space C between the cylindrical spindle 15 and the wheel mounting cylinder 19. The old lubricating oil 100 having a high oil temperature can be prevented from staying in the annular space C, and the circulation (discharge) performance of the lubricating oil 100 in the annular space C can be improved. be able to.

  The bearings 20 and 21 provided between the cylindrical spindle 15 and the wheel mounting cylinder 19 can be supplied with highly circulated lubricating oil 100 that circulates in the annular space C toward the suction port 69A of the discharge pipe 69. The bearings 20 and 21 can always be kept in a lubrication state with the new lubricating oil 100, and the lubricating oil 100 at this time is smoothly discharged to the outside of the wheel mounting cylinder 19 (annular space C) via the discharge pipe 69. be able to.

  Further, the flange portion 15C, which is the maximum outer diameter portion of the cylindrical spindle 15, and the carrier 39 at the final stage are formed to have dimensions that are equal to or smaller than the outer diameter dimension D1 (see FIG. 8) of the bearings 20 and 21. The first stage planetary gear speed reduction mechanism 25 is accommodated therein. The planetary gear speed reduction mechanism 34 in the second stage has an inner diameter D4 of the ring gear 36 that is close to the outer diameter dimension D1 of the bearing 21 as illustrated in FIG. 8 and is equal to or smaller than the outer diameter dimension D1 (D4 ≦ D1).

  Further, by bringing the inner diameter D2 of the other side cylinder portion 19B of the wheel mounting cylinder 19 and the disk holding cylinder 22 close to the outer diameter D1 of the bearings 20 and 21 so as to satisfy the above-mentioned equation 1, the dimensional difference between the two ( D2-D1) is reduced to a dimension that is equal to or smaller than the radial dimension D3 by the inner teeth 36A of the ring gear 36.

  For this reason, it is possible to minimize the lubricating oil 100 in the oil reservoir 43 from staying at the other side cylinder portion 19B of the wheel mounting cylinder 19, the lower position of the ring gear 36, and the like. The lubricating oil 100 in the oil reservoir 43 can be circulated well from the side toward the annular space C. The lubricating oil 100 can be smoothly discharged to the outside while being sucked from the annular space C by the discharge pipe 69.

  In addition, since the inner peripheral surface of the one side cylinder portion 19A of the wheel mounting cylinder 19 is an inclined surface 19F inclined downward from the bearing 21 side toward the bearing 20 side, the lubricating oil 100 in the annular space C is the bearing. It is possible to prevent the stagnation between 20 and 21 by the inclined surface 19F, and the discharge performance of the lubricating oil 100 discharged from the discharge pipe 69 to the outside of the wheel mounting cylinder 19 can be enhanced.

  Therefore, according to the present embodiment, the lubricating oil 100 in the oil reservoir 43 can be efficiently circulated toward the discharge pipe 69, and fresh lubricating oil can be supplied to the bearings 20, 21 and the like. . Further, the new lubricating oil 100 in the oil sump 43 can be continuously supplied to the ring gears 27 and 36 of the planetary gear speed reduction mechanisms 25 and 34, and the durability and life of the bearings 20 and 21 and the ring gears 27 and 36, etc. can be maintained. Can be improved.

  Further, since the first stage planetary gear speed reduction mechanism 25 is accommodated inside the cylindrical spindle 15, the dimension of the second stage planetary gear speed reduction mechanism 34 projecting outward from the cylindrical spindle 15 in the axial direction is set. The axial length (full length) of the entire travel drive device 11 can be shortened, and the entire device can be reduced in size and weight.

  Further, since the carriers 30 and 39 of the planetary gear speed reduction mechanisms 25 and 34 are provided on the cylindrical spindle 15 in a non-rotating state, the support pins 29 and 38 for rotatably supporting the planetary gears 28 and 37 are provided on the carrier 30. , 39 together with the conduits 45, 50 of the lubricating oil supply portions 44, 47 can be stably connected to the oil passages 29A, 38A in the support pins 29, 38. .

  Such support pins 29 and 38 are arranged at regular intervals around the sun gears 26 and 35 and form the center of rotation of the planetary gears 28 and 37. The lubricating oil supplied into the 38 oil passages 29A and 38A can be injected radially by the action of the centrifugal force accompanying the rotation of the planetary gears 28 and 37. For example, the planetary gears 28 and 37 and the sun gears 26 and 35 The lubricating oil refined in the form of a mist can be supplied almost evenly to the meshing surfaces of the gears, the meshing surfaces of the planetary gears 28 and 37 and the ring gears 27 and 36, and the like.

  Thereby, the lubricating oil can be efficiently supplied to the speed reduction mechanism 24, and the durability and life of each component (gear) of the speed reduction mechanism 24 can be improved. The lubricating oil supplied to the meshing surfaces of the gears is stored in the oil sump 43 by natural fall, and can lubricate, for example, the internal teeth 27A and 36A of the ring gears 27 and 36, and rotate the wheel mounting cylinder. The bearings 20, 21 and the like can be kept in a lubrication state between the non-rotating cylindrical spindle 15.

  The carrier 30 provided in the cylindrical spindle 15 in a non-rotating state is formed with an oil passage 30A as shown by a dotted line in FIG. 7 and FIG. The branch pipe 49 and the conduit 50 of the lubricating oil supply unit 47 can be communicated with each other by the oil passage 30A before and after the carrier 30, and the oil passage 30A of the carrier 30 can be used as a lubricating oil supply passage.

  In addition, the carrier 30 in the non-rotating state can be formed with a liquid hole or the like serving as a brake fluid supply passage at a position different from the oil passage 30A. By utilizing the non-rotating carrier 30, for example, the brake pipes 53 and 54 shown in FIG. 7 can be communicated before and after the carrier 30, and the brake fluid pressure is stabilized with respect to the disc brake 56 of the vehicle. Can be supplied.

  In addition, according to the present embodiment, the last stage carrier 39 is used as a lid that covers the open end side of the cylindrical spindle 15, and the disc brake 56 is fixed to the outer surface of the carrier 39 with the bolts 57 or the like. Therefore, the disc brake 56 can be installed at a position on the radially inner side of the rear wheel 7 (the wheel mounting cylinder 19) and on the axially outer side of the cylindrical spindle 15.

  Therefore, at the time of maintenance of the disc brake 56, for example, the wheel cap 7C (see FIG. 3) of the rear wheel 7 is simply removed from the outside in the axial direction, and the disc 756 is removed without removing the tire 7A, the rim 7B, etc. Maintenance and inspection of the disc brake 56 can be easily performed from the outside in the axial direction of the holding cylinder 22 (the wheel mounting cylinder 19), and workability during maintenance can be improved.

  In the above-described embodiment, the case where the first stage carrier 30 is fixed to the annular convex portion 15A of the cylindrical spindle 15 with the bolt 31 has been described as an example. However, the present invention is not limited to this. For example, the first stage carrier may be integrally formed in the cylindrical spindle 15 using means such as casting or forging. It is sufficient that the configuration is provided in a non-rotating state.

  In the above-described embodiment, the case where the second stage carrier 39 is fixed to the flange portion 15 </ b> C of the cylindrical spindle 15 using the bolt 40 has been described as an example. However, the present invention is not limited to this, and the final stage carrier may be integrally formed on the opening end side of the cylindrical spindle 15 using means such as casting or forging.

  In the above-described embodiment, the case where the speed reduction mechanism 24 is configured by the first-stage and second-stage planetary gear speed reduction mechanisms 25 and 34 has been described as an example. However, the present invention is not limited to this. For example, the speed reduction mechanism may be configured by a planetary gear speed reduction mechanism having only one stage, a planetary gear speed reduction mechanism having three or more stages, or a speed reduction device other than the planetary gear speed reduction mechanism. is there.

  In the above embodiment, the case where the electric motor 17 is used as a drive source has been described as an example. However, the present invention is not limited to this. For example, a hydraulic motor or the like may be used as a drive source of the travel drive device.

  Further, in the above embodiment, the rear wheel drive type dump truck 1 has been described as an example. However, the present invention is not limited to this, and may be applied to, for example, a front-wheel drive type or a four-wheel drive type dump truck that drives both front and rear wheels.

It is a front view which shows the dump truck by embodiment of this invention. It is a block diagram which shows the traveling drive apparatus of a dump truck. It is a front view which expands and shows the rear wheel in FIG. FIG. 4 is a cross-sectional view of the traveling drive device on the rear wheel side as viewed from the direction of arrows IV-IV in FIG. 3 with the wheel cap removed. FIG. 5 is an enlarged cross-sectional view illustrating a motor housing cylinder, a cylindrical spindle, a wheel mounting cylinder, a planetary gear reduction mechanism, and the like in FIG. 4. It is a left view of FIG. 5 which expands and shows a disc brake etc. It is sectional drawing which expands and shows the wheel attachment cylinder and planetary gear reduction mechanism etc. in FIG. It is sectional drawing which expands further and shows the planetary gear reduction mechanism etc. in FIG. It is sectional drawing which expands and shows the sealing apparatus etc. which were provided between the cylindrical spindle in FIG. 7, and a wheel attachment cylinder.

Explanation of symbols

1 Dump truck 2 Car body 3 Vessel 5 Cabin 6 Front wheel 7 Rear wheel (wheel)
8 Engine 9 Alternator (generator)
DESCRIPTION OF SYMBOLS 10 Electric controller 11 Travel drive device 12 Axle housing 13 Suspension cylinder 14 Motor accommodating cylinder 15 Cylindrical spindle 16, 31, 40 Bolt 17 Electric motor (drive source)
18 Rotating shaft 19 Wheel mounting cylinder 19A One side cylinder part 19B Other side cylinder part 19F Inclined surface (guide surface)
20, 21 Bearing 22 Disc holding cylinder 22A Disc 24 Reduction mechanism 25, 34 Planetary gear reduction mechanism 26, 35 Sun gear 27, 36 Ring gear 28, 37 Planetary gear 29, 38 Support pin 29A, 38A Oil passage 30, 39 Carrier 33 Cup Ring 43 Oil reservoir 44, 47 Lubricating oil supply part 45, 50 Conduit 46 Supply pipe 49 Branch pipe 51 Supply pipe 56 Disc brake 60, 71 Seal device 61 Retainer (seal mounting body)
64 O-ring (seal member)
68 Lubricating oil discharge part 69 Drain pipe 72 Wedge member 73 Undulating cylinder 100 Lubricating oil

Claims (5)

A cylindrical axle housing that is attached to the body of the dump truck in a non-rotating state, a drive source that is provided on the axle housing and that rotates the rotating shaft, and is provided rotatably on the outer peripheral side of the axle housing via a bearing. Traveling of a dump truck comprising a wheel mounting cylinder to which a wheel is mounted, and a speed reduction mechanism provided between the wheel mounting cylinder and the axle housing to transmit the rotation of the rotary shaft to the wheel mounting cylinder at a reduced speed. In the drive device,
Provided inside the axle housing is a lubricating oil supply section that supplies lubricating oil toward the speed reduction mechanism,
Inside the axle housing and the wheel mounting cylinder, there is provided an oil sump that keeps the lubricating oil supplied from the lubricating oil supply part in the upper and lower positions and keeps the bearing in a lubricated state,
Lubricating oil discharge section for sucking and discharging the lubricating oil in the oil reservoir from between the wheel mounting cylinder and the axle housing to the lower side in the upper and lower direction on the outer peripheral side of the axle housing A dump truck travel drive apparatus characterized by comprising   The reduction mechanism is configured by a plurality of planetary gear reduction mechanisms including a sun gear, a ring gear, a planetary gear, and a carrier, and the last stage planetary gear reduction mechanism of the plurality of planetary gear reduction mechanisms includes the ring gear. The traveling drive device for a dump truck according to claim 1, wherein the traveling drive device is configured to have an inner diameter close to an outer diameter of the bearing.   The travel drive device for a dump truck according to claim 1 or 2, wherein a guide surface for guiding the lubricating oil in the oil reservoir toward the lubricating oil discharge portion side is provided on an inner peripheral surface of the wheel mounting cylinder. .   The axle housing is provided with a cylindrical drive source accommodating portion that accommodates the drive source therein, and is connected to the drive source accommodating portion. The axle housing accommodates a part of the speed reduction mechanism on the inner peripheral side, and the outer peripheral side is the bearing. A cylindrical spindle for rotatably supporting the wheel mounting cylinder via a ring, and an annular seal mounting body to which a sealing member for liquid-tightly sealing the wheel mounting cylinder is attached to the cylindrical spindle. 4. The dump truck according to claim 1, wherein the lubricating oil discharge portion is constituted by a discharge pipe provided to be connected to the seal mounting body at a position below the cylindrical spindle. Travel drive device.   The speed reduction mechanism is constituted by a planetary gear speed reduction mechanism in which a carrier that rotatably supports a plurality of planetary gears via a support pin is provided in the axle housing in a non-rotating state, and the lubricating oil supply section has one side A lubricating oil conduit connected to a supply source of lubricating oil and having the other side extending inside the axle housing and connected to a support pin of the planetary gear, and a lubricating oil formed on the support pin from the conduit to the planetary gear The traveling drive device for a dump truck according to claim 1, 2, 3, or 4, comprising a lubricating oil passage that circulates toward the vehicle.

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